Improved Interleaved Buck Converter with High-Step Down Conversion Ratio and Soft-Switching

This article proposes a new interleaved buck converter with a high step-down conversion ratio and soft-switching. The soft-switching conditions for the main IGBTs are achieved with the aid of a simple auxiliary circuit, which comprises a resonant inductor, a resonant capacitor, and a diode. A new interleaved buck converter is realized by adopting two auxiliary circuits separately connected to each one of the legs to provide zero voltage switching (ZVS) and zero current switching (ZCS) turn-on operation. The major advantages of this converter are reduced switching losses, a high step-down ratio, reduced voltage stresses, and no limitation on duty ratio. To validate the theoretical analysis, a laboratory prototype of a 200 V-60 V converter system has been developed and achieved an efficiency of 96% at 250 W output power.